there are long standing bugs in the dev scanning code of lvm1,
did you try using the devfs name (even if you don't mount devfs you can
create the device file manually)
you could also add some more info instead of requoting yourself
eg: contents of the damned /proc/partitions
which version of lvm tools are you running
output of lvmdiskscan
lvmdiskscan -d
pvcreate -d
and so on.